1. Field of the Invention
The present invention relates to a system of an internal combustion engine mounted on an automobile or the like, and particularly relates to a high pressure fuel supply system including a high pressure fuel pump.
2. Description of the Prior Art
In an in-cylinder injection engine which has been developed in recent years, fuel injection by a fuel injection valve is carried out directly into a combustion chamber of a cylinder, and combustion of fuel is promoted by reducing a particle size of the fuel injected from the fuel injection valve, so that reduction of emission gas substances, enhancement of engine output power and the like are achieved.
Here, in order to reduce the particle size of the fuel injected from the fuel injection valve, a means for increasing pressure of the fuel is required. Until now, there have been proposed various arts relating to a high pressure fuel supply system which is constituted by a fuel injection valve, a pressure accumulation container (hereinafter, called a common rail) for accumulating fuel to be injected from the fuel injection valve under pressure, a high pressure fuel pump for supplying the fuel to the common rail, and the like. Fuel efficiency and emission gas can be more improved when the fuel pressure in the common rail is changed in accordance with the operating state of the internal combustion engine. In this case, if target fuel pressure and actual fuel pressure of the fuel pressure deviate from each other, the fuel efficiency and the emission gas are likely to be worsened conversely.
In a conventional high pressure fuel supply system, the fuel pressure in the common rail is controlled by regulating the balance of the high pressure pump which supplies fuel to the common rail and the fuel injection valve which injects the fuel contained in the common rail (see JP-A-2010-25102).